The object of the invention is an apparatus for the corrosion protection of containers for the long time storage of radioactive materials, especially from spent fuel elements, in suitable geological formations.
Spent fuel elements are worked up after a temporary storage in water basins either immediately or after a limited further intermediate storage up. Thereby, the nuclear fuel and breeder material of the fission products are separated and returned to the fuel cycle. The fission products are conditioned according to known processes, for the most part using large amounts of valuable materials, as for example, lead and copper and are finally stored in non-retrievable manner in suitable geological formations such as salt blocks.
Furthermore, it has been proposed (reports of the Kernforschungszentrum Karlsruhe KFK 2535 and 2650) not to work up the irradiated fuel elements in the foreseeable future, to give up the fuel and breeder materials in them and, after a suitable decay time in storages provided therefore, finally store the fuel elements in salt formations. The storage time of the spent fuel elements thus can be hundreds of years.
Because of the undetermined storage time, special requirements are placed on such containers suited for the long time and final storage. Increasing the difficulty is the fact that the container storage must be accessible only with difficulty, and consequently limits are placed on the possiblity of supervision or supervision is even excluded.
Concepts are known which in part involve great expense to store the spent fuel elements or radioactive waste by means of containers made of metal or concrete in geological formations as, e.g. in dry salt blocks (Report of the Kernforschungszentrum Karlsruhe KFK 3000).
However, the use of concrete is problematical since long time experience over hundreds or in a give case over thousands of years naturally is not present. Metal containers, e.g. of steel, cast iron, especially spherical graphite cast iron, lead, copper, or other materials also have disadvantages. Among others, these are partially in the production costs, above all, however, in the area of corrosion, since among others water penetration, even though there is only a slight possibility of occurrence, must be included in safety considerations.
The invention therefore is based on the problem of providing an apparatus for the corrosion protection of containers for the long time storage of radioactive materials, especially spent fuel elements, in suitable geological formations which avoid the corrosion of the containers in the event of unexpected occurrence of water or at least delay and reduce such corrosion.